Certain aircraft use stiffened parts made of composite material. The stiffened parts may contain flat areas and corners. A corner of a stiffened part is referred to as a “corner radius.”
Structural health of a stiffened part can be determined by non-destructive inspection such as ultrasonic testing. A corner radius of a stiffened part can be inspected by a probe including a radiused shoe that holds an ultrasonic transducer. During testing, the shoe's radius is pressed against a corner radius of the part, the transducer is acoustically coupled to the part (e.g., with water), and the shoe is slid along the corner radius. As the shoe is being slid, the transducer operates in pulse/echo mode to generate sound pulses, which are transmitted through the corner radius. Reflected sound pulses indicate whether the corner radius contains a crack, void, delamination, etc.
In certain aircraft, stiffened parts have corner radii with a wide range of sizes and angles. However, one size shoe does not fit all, so different shoes are customized to match the different radii.
Designing a probe for each change in angles, and designing a probe for each change in radius size requires a large inventory of probes and transducers. A large inventory of probes and transducers can be very expensive.